Podophyllic Aldehyde, a Podophyllotoxin Derivate, Elicits Different Cell Cycle Profiles Depending on the Tumor Cell Line: A Systematic Proteomic Analysis

When new antitumor therapy drugs are discovered, it is essential to address new target molecules from the point of view of chemical structure and to carry out efficient and systematic evaluation. In the case of natural products and derived compounds, it is of special importance to investigate chemomodulation to further explore antitumoral pharmacological activities. In this work, the compound podophyllic aldehyde, a cyclolignan derived from the chemomodulation of the natural product podophyllotoxin, has been evaluated for its viability, influence on the cell cycle, and effects on intracellular signaling. We used functional proteomics characterization for the evaluation. Compared with the FDA-approved drug etoposide (another podophyllotoxin derivative), we found interesting results regarding the cytotoxicity of podophyllic aldehyde. In addition, we were able to observe the effect of mitotic arrest in the treated cells. The use of podophyllic aldehyde resulted in increased cytotoxicity in solid tumor cell lines, compared to etoposide, and blocked the cycle more successfully than etoposide. High-throughput analysis of the deregulated proteins revealed a selective antimitotic mechanism of action of podophyllic aldehyde in the HT-29 cell line, in contrast with other solid and hematological tumor lines. Also, the apoptotic profile of podophyllic aldehyde was deciphered. The cell death mechanism is activated independently of the cell cycle profile. The results of these targeted analyses have also shown a significant response to the signaling of kinases, key proteins involved in signaling cascades for cell proliferation or metastasis. Thanks to this comprehensive analysis of podophyllic aldehyde, remarkable cytotoxic, antimitotic, and other antitumoral features have been discovered that will repurpose this compound for further chemical transformations and antitumoral analysis.

miRNome Profiling of Extracellular Vesicles in Patients With Severe COVID-19 and Identification of Predictors of Mortality

BACKGROUND

Extracellular vesicles (EVs), containing microRNAs (miRNAs) and other molecules, play a central role in intercellular communication, especially in viral infections caused by SARS-CoV-2. This study explores the miRNA profiles in plasma-derived EVs from patients with severe COVID-19 vs controls, identifying potential mortality predictors.

METHODS

This prospective study included 36 patients with severe COVID-19 and 33 controls without COVID-19. EV-derived miRNAs were sequenced, and bioinformatics and differential expression analysis between groups were performed. The plasma miRNA profile of an additional cohort of patients with severe COVID-19 (n = 32) and controls (n = 12) was used to compare with our data. Survival analysis identified potential mortality predictors among the significantly differentially expressed (SDE) miRNAs in EVs.

RESULTS

Patients with severe COVID-19 showed 50 SDE miRNAs in plasma-derived EVs. These miRNAs were associated with pathways related to inflammation and cell adhesion. Fifteen of these plasma-derived EV miRNAs were SDE in the plasma of severe cases vs controls. Two miRNAs, hsa-miR-1469 and hsa-miR-6124, were identified as strong mortality predictors with an area under the receiver operating characteristic curve of 0.938.

CONCLUSIONS

This research provides insights into the role of miRNAs within EVs in severe COVID-19 and their potential as clinical biomarkers for mortality.

Insights into podophyllotoxin lactone features: New cyclolignans as potential dual tubulin-topoisomerase II inhibitors

Chemomodulation of natural cyclolignans as podophyllotoxin has been a successful approach to obtain semisynthetic bioactive derivates. One example of this approach is the FDA-approved drug etoposide for solid and hematological tumors. It differs from the antimitotic activity of the natural product in its mechanism of action, this drug being a topoisomerase II inhibitor instead of a tubulin antimitotic. Within the molecular requirements for the activity of these compounds, the trans-γ-lactone moiety presented in the parent compound has always been a feature to be explored to chemomodulate its bioactivity. In this study, we have obtained different compounds that comply with the molecular characteristics for antitubulin and antitopoisomerase II activity combined in a single molecule. Furthermore, we explored the influence of the trans-lactone moiety on the final activity, finding that the cis-lactone was also interesting in terms of bioactivity. The best values of cytotoxicity and cell cycle inhibition were obtained for a compound lacking the lactone ring, thus mimicking the podophyllic aldehyde functionalization, a selective antimitotic podophyllotoxin derivate. The analogs with cis-lactone also presented interesting cytotoxic activity. The present study illustrates the potential of the chemomodulation of natural products such as natural cyclolignan podophyllotoxin derivates for the discovery of new antitumor agents.